Mf2

- Added Manifest.in to include requirements and docs in source distribution

- Added documentation for adjustable functions
- Added documentation to bounds variables and MultiFidelityFunction instances
- Expanded getting-started page of documentation
- Documentation: added generic introduction
- Updated JOSS paper:
* added acknowledgements,
* added Forrester reference
* itemized functions included in package
* extended introduction of multi-fidelity definition
* added scalability comparison script + results figure
* updated surjanovic and bingham entry in bib-file
- Added README badges: conda, JOSS, license. Now formatted in a table
- Dependencies automatically installed upon install
- Requirements for tests moved to `requirements-dev.txt`
- Separated requirements into regular 'requirements' and 'requirements-dev'
- Added requirements-dev install instruction to README
- __init__ now uses pkg_resources to version number, defined in setup.py
- Added simple logo to documentation
- Added conda install instruction
- Clarified available fidelity levels and their use in docs/getting-started
- Added installation page to docs
- documentation now shows difference between in- or excluding `fidelity_names=`
in MultiFidelityFunction definition
- Adjustable functions: bounds now separate variables, docstrings updated with correct parameter values for high-low equality
- Tests cleanup: removed old 'import mf2 as mff', paths fixed using pyprojroot
- Update README: added correct module-script instruction for create_regression_files
- Updated travis script to install the package
- Bugfix: fixed mistake in low-fidelity Forrester definition
- Added example-usage to docs: reproducing fig. 1 from Forrester 2007
- Bugfix: mistake in low-fidelity of Forrester function
- Included changelog

- row_vectorize decorator on functions replaced by np.atleast_2d call
- Improved docstrings for all functions
- Added JOSS paper
- Added README badges: PyPI, gitter chat
- Added README sections: Installation, Example Usage, Contributing and Contact
- Added CI for Python3.8
- Upated PyPI page specifiers: markdown text + Python versions (3.6-3.8)

- Added GPL 3.0 license
- Renamed package: multifidelityfunctions -> mf2

- Correlation-adjustable functions moved to .adjustable subpackage
- Refactored benchmarks to test into single definition list
- Added docs for all non-adjustable functions
- Added docstrings for MultiFidelityFunction properties

- First release